Central Appalachian Basic Ash – Hickory Woodland
This rare plant community occurs on the exposed and weathered south-facing slopes of Round Top Mountain. The rather open terrain is completely exposed to the elements and shallow soils drape over and in between huge flat and convex rock outcroppings. Variation, dictated by the islands of convex-sloped bedrock, results in a patchwork of full sun and partial shade conditions. Pockets of soil accumulate to great depths in places, allowing for larger trees to grow. However, due to the lack of root grip, trees can only grow to moderate heights before winds topple them over. Therefore the site is littered with the decomposing logs of a wide variety of sizes and species of shrubs and trees.
Despite the shallow rocky soils, the substrate is quite fertile. The high levels of calcium and magnesium have resulted in a unique plant community. Due to the base-rich soils these habitat types tend to have issues with non-native species. Thus this habitat is significantly impacted by non-native exotic species, making it a reduced version of the intact and remarkable outcrop barrens that occur 500′ south (and off of current RMNA property).
The upper canopy, being about 50% open, consists entirely of white ash (Fraxinus americana).
The middle canopy remains mostly open and is occupied by scattered white ash (Fraxinus americana), eastern red cedar (Juniperus virginiana), pignut hickory (Carya glabra), and post oak (Quercus stellata).
The lower canopy is nearly empty, containing scattered specimens of pignut hickory (Carya glabra), tree-of-heaven (Ailanthus altissima), and redbud (Cercis Canadensis).
The shrub layer is highly compromised by non-native exotics such as wineberry (Rubus phoenicoloasius). Remnants of a once healthy ecosystem are seen in devil’s walking stick (Aralia spinosa) colonies, dwarf hackberry (Celtis tenuifolia) and blackhaw (Viburnum prunifolium).
The herbaceous layer is heavily impacted by the non-native species, Japanese stiltgrass (Microstegium vamineum). Blunt-lobed woodsia (Woodsia obtusa) occurs in patches among extensive colonies of yellow fumewort (Corydalis flavula). A Grimmia species of dry rock moss graces the rock faces, reminding us that these expansive south-facing rocks likely held a rich assemblage of Piedmont Mafic Barren species long ago.